If your business is growing, VAT is one of those milestones that can sneak up on you. Cross a certain level of turnover and registration stops being optional — it becomes a legal requirement, with penalties if you miss the deadline. And once you are registered, there is a second decision to make: do you account for VAT the standard way, or join HMRC's Flat Rate Scheme to simplify your paperwork? This guide walks through both, in plain English, so you know where you stand.
When you have to register for VAT
You must register for VAT if your VAT-taxable turnover goes over the registration threshold, which is currently £90,000. Turnover here means the total of everything you sell that is not exempt from VAT — not your profit, and not just your invoices to VAT-registered customers.
There are two separate tests, and it is easy to trip over the first one:
- The backward-looking test. At the end of every month, add up your VAT-taxable turnover for the previous 12 months on a rolling basis. If that rolling total goes over £90,000, you must register within 30 days of the end of the month in which you crossed it. Your registration then takes effect from the first day of the second month after you went over.
- The forward-looking test. If you expect your turnover to go over £90,000 in the next 30 days alone — say you have just won a large contract — you must register by the end of that 30-day period, and registration is effective from the date you realised.
The rolling nature of the first test catches a lot of people out. It is not about your accounting year or the tax year; it is a moving 12-month window that you should be checking every single month once you are getting close.
There is also a deregistration threshold of £88,000. If your taxable turnover falls below this, you can apply to cancel your registration — though whether that is the right move depends on your customers and your costs.
Should you register voluntarily?
You can register before you hit the threshold, and for some businesses that makes sense. If most of your customers are themselves VAT-registered, they can reclaim the VAT you charge, so adding it does not really cost them anything — and voluntary registration lets you reclaim the VAT on your own purchases and equipment. That can be worth real money if you are investing in kit or software.
If your customers are mainly members of the public, the picture is different: adding 20% to your prices either makes you less competitive or eats into your margin. There is no single right answer here, which is exactly the kind of decision it pays to talk through before you commit.
The VAT Flat Rate Scheme, explained
Standard VAT accounting means charging VAT on your sales, reclaiming VAT on your purchases, and paying HMRC the difference. It is accurate, but it means tracking the VAT on every expense.
The Flat Rate Scheme (FRS) is designed to cut down that admin, mainly for smaller businesses. Instead of working out the VAT on every purchase, you still charge your customers the normal 20%, but you pay HMRC a single fixed percentage of your gross (VAT-inclusive) turnover. That percentage depends on your trade sector.
You can join the Flat Rate Scheme if you expect your VAT-taxable turnover to be £150,000 or less (excluding VAT) in the next 12 months. You have to leave the scheme once your total business income goes over £230,000 (including VAT), or if you expect it to on the anniversary of joining.
As an incentive, there is a 1% discount on your flat rate for the first year you are VAT-registered — a small but welcome sweetener for newly registered businesses.
Watch out for the "limited cost trader" rate
The Flat Rate Scheme used to be a genuine money-saver for many service businesses. Then HMRC introduced the limited cost trader (or "limited cost business") rules to stop that.
If your spending on goods is very low — less than 2% of your turnover, or less than £1,000 a year — you are classed as a limited cost trader and must use a flat rate of 16.5%, whichever sector you are in. Because that 16.5% applies to your VAT-inclusive turnover, it works out at roughly 19.8% of your net sales, leaving almost nothing of the VAT you have charged. Crucially, spending on services, subcontractors, and most software does not count towards that goods test — so a lot of consultants, freelancers and agencies fall into the limited cost category without realising it.
The practical upshot: the Flat Rate Scheme can still simplify life and save money for some businesses, but for many service-based sole traders and freelancers it no longer beats standard VAT accounting. It is worth running the numbers both ways before you choose.
What this means for you
Whether you are a growing sole trader approaching the threshold, or a limited company weighing up the Flat Rate Scheme, the key is to keep an eye on that rolling 12-month figure and to make the accounting choice deliberately rather than by default. Register late and you can face penalties plus a bill for VAT you never charged your customers; pick the wrong scheme and you could hand HMRC more than you need to.
It is also worth remembering that VAT does not stand alone. Most VAT-registered businesses now keep digital records and file returns through Making Tax Digital-compatible software, so getting your bookkeeping set up properly from day one saves a lot of stress later.
If you are not sure whether you need to register, whether voluntary registration would help, or which VAT scheme suits your business, we can look at your specific numbers and give you a clear recommendation. Get an instant quote for our accountancy services, or book a call and we will talk it through with no obligation.
This article is general guidance, not personal tax advice. Your circumstances may differ, so please get in touch for advice tailored to you.